How much faster will neon effuse than krypton, given that the molar mass of krypton is
83.8 grams and that of neon is 20.18 grams?

Effusion is the escape of a gas through a small hole.

Graham Law states that the speed of effusion is inversely related to the square root of its molar mass:

effusion speed = K * 1 / √ molar mass)

=> effusion speed of gas A        √(molar mass of gas B)
       = 
     effusion speed of gas B         √(molar mass of gas A)

=> efussion speed of Ne          √(83.8)
         =        = 2.04
     effusion speed of Kr            √(20.18

=> effusion speed of Ne = 2.04 * effusion speed of Kr.

approximated twice.